Connector with washer cap



Jan. 23, 1940-. M. LEE ET AL 2,188,135

CONNECTOR WITH WASHER CAP Filed June 16, I937 INVENTORS MARVIN LEE &JULIAN RosoFF BY Patented Jan. 23, 1940 UNITED STATES 2,188,135 comc'ronwrrn WASHER car Marvin Lee, Rye, and Julian Rogoff, New York, N. Y.,assignors to Burndy Engineering Co. Inc., a corporation of New YorkApplication June 16, 193'], Serial No. 148,491

4 Claims. (Cl. 173-269) This invention relates to connectors and moreparticularly to connectors employing caps or pressure transmittingelements between nut and ca 1e.

6 In Patent No. 2,049,409 issued to Bern Dibner, a cap of this nature isdisclosed. These caps are either cast or forged. When such a cap isclamped on soft drawn copper cable, it is necessary to provide somemeans of locking the joint .10 against loosening from vibration. This isusually done by using a lockwasher which is inserted between the nut andthe 'cap.

This fourth element addedg to the cost, and.

further made it necessaryfoi the installer to take into consideration anadditional piece to handle, which would be burdensome-in inconvenientlocations; waste time, and increase the possibility of parts dropping.

Accordingly, a primary object of our inven- 1 tion consists in providinga cap that possesses all the features of a lockwasher in a singleunitary construction, thus'eliminating an extra ele-v ment.

We have found that when soft drawn cables are u clamped in thesesolderless electrical connectors,

they have a tendency to be gradually relieved of the clamping pressurefor several reasons.

One reason is that the strands of the cable,

being clamped under high pressure, will gradually 80 distort andmeshintocloser relationship with a resultant smaller diameter.

Another cause is the expansion and contraction of the cable andconnector because of tem- 2 perature changes. If there is any differenceat Sliall in the thermal coeflicients of expansion-of the cable and theconnector, a change in temperature will cause an uneven expansion orcontraction. A cycle of expansion and contraction I may cause the cableto loosen. do A third reason is the creep of the cable, which, beingpreferably of copper possessing a high conductivity, is soft and doesnot have a yield point. The constant tension or pressure -willpermanently deform the cable, loosening the 45 connection, and reducingits electrical emciency. Another object, therefore, is to provide a capcapable of maintaining a constant pressure on the cable to a degreeunobtainable byan ordinary cap and lockwasher. 60 In addition, thesecaps or pressure transmitting elements had'broad pressure applyingsurfaces, so that the cable would not be deeply indented by pointcontacts with greati pressure concentrations.

All these features necessitated the use ofa solidly forged or castconnector possessmg considerable weight, increasing the shippingcharges, and adding to the cost of the connector.

A further object, therefore, is to provide a cap, weighing a fraction ofthe average cap, yet possessing suiiicient strength to enable the use ofhigh pressures to insure good electrical joint efilciency and containingsufliciently large pressure areas to avoid point contacts with thecable.

We attain these and other objects, and accom- 10 plish our results byproviding a sheet metal combined pressure cap and washer, as will bereadily apparent from a consideration of the following description andclaims taken together with the accompanying drawing in which:

Fig. 1 is a side view of a connector provided with washer cap.

Fig. 2 is an end view of the same.

Fig. 3 is a top view.

Fig. 4 is a top view of the cap. 20

Fig. 5 is a side view of the same.

Fig. 6 is a front view.

Fig. '7 is a side view of our cap applied to another type of connector.

Fig. 8 is a sectional view through the line 8-8 of Fig. 4. v

Fig. 9 illustrates the cap with outwardlyv extending arms.

Referring more particularly to Fig 1, reference numeral l0 designatesthe complete connector in which a cable is provided with a terminalblock l2.

' The connector is provided with main and auxiliary clamping members [8and It, with troughs I 5 and I6 forming a socket in members l3 and Mrespectively. I

The cable ll passes through the eye ll, .of the eyebolt [8, whichis'integral with the main socket member and rises normally thereof,terminating in the threaded bolt section IS. A nut 20 threadedly,engages the bolt IQ for applying pressure to the cable. 1 a.

I The auxiliary socket member II is in the form of a sheet metalcap'having an aperture 2| centrally located on the upper surface 22. 5

The sheet metal cap is preferably drawn into a rectangular cup shapedsection with two opposite arms 23 and 24 extending beyond the sides 25and 26 and inwardly-drawn or outwardl see Fig. 9) and formed into atrough it, previously described.

While the cap illustrated is rectangular in form, the particular shapeis immaterial, the necessary' feature residing ina contact surface forthe nut, and two normally extending trough u shaped arms for receivingthe cylindrically shaped cable.

The trough shaped arms 23 and 24 extend inwardly approximately to thesides of the eyebolt l8 and the extreme edges 21 and 2B are downwardlypositioned so that they will first engage the cable before the surfaceof the trough comes in contact with the surface of the cable.

The entire cap H, is made of springy metal, the two arms 23 and 24,resiliently giving under the applied pressure until there is a surfacecontact of trough and cable.

The spring effect of the cap may be increased or decreased by raising orlowering the two other side walls, the lowering of these walls reducingthe length of the sides 25 and 26 to' which the trough arms areattached. This will make the trough arms more rigid and tend to preventtheir springing action. Thus when the other side walls have beenremoved, the sections 25 and 26 remaining provide maximum resiliency tothe arms.

The eyebolt l8 may be constructed free of the terminal block l2, andmade into an auxiliary socket member, as shown in Fig. 7; the pressureblock becomes the current carrying member and its design may be modifiedaccordingly. The terminal block 29 shown in this figure is insertedbetween the cap and nut, the eyebolt 30, entering an aperture 3| in theextension 32 of the terminal block 29, and the nut tightened as before.

When identical connectors, one with the sheet metal cap and one with thesolid forged cap are tightened with identical values of wrench torque,

there is an increase in the pull-out value of the.

sheet metal cap over the forged cap of between 20 to 50%. We attributethis increase in pullout value to the effect of the edges 2!- and 28biting in the'cable before the pressure areas engage, holding the cables'ecurely in place.

We have thus described our invention, but we desire it understood thatit is not confined to the particular forms or uses shown and described,

the same being merely illustrative, and that the invention may becarried out in other ways without departing from, the spirit ofourinvention, such as the use of a washer cap employing our invention ina. connector joining two cables together, instead of the terminal shownand, therefore, we claim broadly the right to employ all equivalentinstrumentalities coming within the-- What we claim and desire to secureby Letters Patent, is as follows:

1. A connector for electric cables comprising a plurality oi cableclamping members forming a socket for receiving a cable, one of which ismade of sheet metal having a surface upon which the clamping pressure isapplied, and integral therewith, a pair of sections extendingtransversely to clamping pressure is applied, side walls extendingtransversely to said surface and terminating in a pair of oppositelypositioned resilient arms having cable clamping sections extendinglongitudinally of the cable receiving socket, and means for applyingpressure to the surface of the sheet metal cable engaging member forclamping-the cable between the members.

3. A connector for electric cables comprising a plurality of cableclamping members forming a socket for receiving a cable, one of saidcable clamping members having extending threaded means, the other ofwhich is made of sheet metal having an apertured surface upon which theclamping pressure is applied, side walls extending transversely to saidsurface and terminating in a pair of oppositely positioned resilientarms having cable clamping sections extending longitudinally of thecable receiving socket, and a nut for engaging the threaded meansprojecting through the apertured sheet metal surface for applyingpressure thereto and clamping the cable between the members.

4. A connector for electric cables comprising a plurality of cableclamping members forming asocket for receiving a cable, one of saidcable clamping members having extending threaded means, the other ofwhich is made of sheet metal having an apertured surface upon which theclamping pressure is applied, side walls extending transversely to saidsurface and terminating I clamping members, having a plurality ofapertures, one for receiving the threaded means and the other forfixedly attaching said connector.

JULIAN ROGOFF.

